The present application claims the priority of the commonly owned copending German patent application Serial No. 100 35 962.3 filed Jul. 20, 2000. The disclosure of the above-referenced German patent application, as well as that of each US and foreign patent and patent application identified in the specification of the present application, is incorporated herein by reference.
The invention relates to improvements in methods of and in apparatus for regulating the density of elongated streams of comminuted natural, artificial and/or reconstituted tobacco or other particulate material prior to processing or further processing of such material, e.g., in a tobacco rod making machine. More particularly, the invention relates to improvements in methods of and in apparatus for making one or more streams or flows of discrete particles, such as comminuted tobacco ribs and/or comminuted tobacco leaf laminae. Still more particularly, the invention relates to improvements in methods and apparatus of the type disclosed in commonly owned German patent application Serial No. 43 36 453 A 1 of Manfred Kaluza published Apr. 27, 1993.
The published German patent application of Kaluza discloses a hopper (also called distributor) which is designed to supply one or more flows of tobacco particles to the rod forming station of a cigarette rod making or an analogous tobacco processing machine. The hopper of Kaluza employs a downwardly extending and downwardly diverging funnel-shaped housing the upper end portion of which receives a continuous stream of tobacco particles from a drum-shaped carded conveyor cooperating with a rapidly driven picker roller and being located at the lower end of an upright tobacco supplying duct. The hopper has two confronting sidewalls which flank a downwardly extending path for tobacco particles being propelled downwardly by the aforementioned picker roller. The sidewalls have orifices forming part of nozzles which admit jets of air transversely against the respective sides of the descending particle stream. The nozzles at one of the sidewalls are staggered vertically relative to the nozzles at the other sidewall so that successive increments of the descending stream are alternatingly deflected and thereby loosened by the jets of gaseous fluid issuing from the orifices of the nozzles at the respective sidewalls of the duct. Such treatment of the descending stream of tobacco particles results in a loosening or singularizing of the body or mass of downwardly advancing tobacco particles. The thus pretreated partially loosened descending stream is thereupon subjected to additional mechanical and pneumatic treatments which are intended to impart to the developing flow of tobacco particles an optimum consistency for conversion into a tobacco rod which is ready to be converted into a so-called filler adapted to be confined in a tubular envelope consisting of cigarette paper or other suitable wrapping material.
The additional mechanical and/or pneumatic treatment is intended to segregate fragments of tobacco ribs from so-called tobacco leaf laminae (shredded tobacco leaves) prior to draping of the rod-like filler into the running web of cigarette paper or the like. The segregation of comminuted ribs from the comminuted (such as shredded) tobacco leaf laminae is intended to reduce the likelihood of undesirable puncturing of the cigarette paper web by fragments of relatively hard tobacco ribs.
An apparatus similar to that disclosed in the published German patent application of Kaluza is disclosed in U.S. patent application Ser. No. 09/482,679 corresponding to published German patent application No. 199 01087.
An object of the invention is to provide a novel and improved method of manipulating accumulations of particulate material, such as mixtures of comminuted tobacco ribs and tobacco leaf laminae, in a gentle and highly reliable (reproducible) manner.
Another object of the invention is to provide a novel and improved method of processing streams or flows of particles which are about to be converted into the rod-like fillers of cigarettes, cigarillos and analogous smokers"" products.
A further object of the present invention is to provide a method which renders it possible to eliminate so-called density holes (randomly occurring regions or portions of a tobacco stream wherein the density deviates appreciably from the densities of neighbouring portions) in the flow of tobacco particles being caused to advance through the distributor or hopper of a cigarette rod making machine or an analogous machine for the mass production of smokers"" products.
An additional object of the invention is to provide a method which renders it possible to carry out a novel and improved treatment of a tobacco stream about to be converted into the filler or fillers of one or more continuous cigarette rods or the like.
Still another object of the invention is to provide a method which renders it possible to enhance the homogeneousness of the rod-shaped filler of a continuous rod that can be subdivided into a file of plain cigarettes, cigars, cigarillos or analogous smokers"" products.
A further object of the invention is to provide a novel and improved distributor or hopper for use in a machine for making plain cigarettes, cigarillos, cigars and analogous smokers"" products.
Another object of the instant invention is to provide a novel and improved combination of parts which can be utilized to increase or enhance the homogeneousness of one or more streams of fibrous particles, such as comminuted tobacco leaves.
An additional object of the invention is to provide a novel and improved system of nozzles which can be utilized in the distributor or hopper of a cigarette rod making or an analogous machine.
Still another object of the invention is to provide a novel and improved apparatus for homogenizing a stream of shredded tobacco leaf laminae, with or without tobacco ribs, in the distributor or hopper of a cigarette rod making machine.
A further object of the instant invention is to provide novel and improved cigarettes, cigarillos, cigars or analogous rod-shaped smokers"" products.
Another object of this invention is to enhance the homogeneousness of the tobacco fillers in cigarettes, cigars, cigarillos or other rod-shaped tobacco-containing products
One feature of the present invention resides in the provision of an apparatus for regulating the density of elongated streams of particulate material, such as comminuted tobacco leaves. The improved apparatus comprises a conveyor having an inlet and at least one outlet and defining an elongated path extending from the inlet to the at least one outlet, and means for treating a stream of particulate material in the conveyor. The treating means comprises a compacting unit which is designed to densify successive increments of the stream at the inlet with attendant conversion of successive increments of the stream into successive increments of at least one modified stream (hereinafter called flow to distinguish it from the stream which is being admitted into the path) wherein at least some of the particles are interlaced with and/or otherwise brought closer to each other, and at least one means for changing the speed of successive increments of the flow in the conveyor to at least substantially singularize the particles not later than at the at least one outlet of the conveyor.
The apparatus can further comprise means (such as an at least substantially upright duct and/or a so-called combing roller or an equivalent thereof) for advancing successive increments of the stream toward the inlet along a second path, and means (such as a so-called picker roller which co-operates with the combing roller) for transferring successive increments of the stream from the second path into the inlet of the elongated path.
In accordance with a presently preferred embodiment, the compacting unit includes at least one pneumatic stream compacting device; such compacting device can comprise at least one nozzle which is arranged to direct at least one stream (hereinafter called jet to distinguish it from the aforementioned stream of particulate material) of a compressed gaseous fluid against successive increments of the stream in the elongated path.
The conveyor can be set up to advance the increments of the stream of particulate material at a first speed, and the speed changing means can include means (such as one or more compressed air discharging nozzles or a mechanical means such as a picker roller or a brushing roller or brush cylinder) for advancing successive increments of the at least one flow at a different second speed. Such speed changing means can be provided with a surface which extends in the conveyor in a direction from the inlet toward the at least one outlet and defines a portion of the elongated path. At least a portion of such surface can have an arcuate shape. For example, the surface can include an at least substantially horizontal first portion and a second portion which slopes upwardly in a direction from the at least substantially horizontal first portion toward the at least one outlet. The slope of the second portion of the aforementioned surface preferably increases in a direction toward the at least one outlet. The at least one speed changing means of such apparatus can further include at least one nozzle which is provided at the aforementioned surface and is arranged to direct at least one jet of air or another suitable gaseous fluid against successive increments of the flow in the conveyor. The at least one nozzle can be provided at (e.g., in) an at least substantially smooth portion of the surface.
As already mentioned above, the at least one speed changing means can include at least one nozzle which is arranged to direct at least one particle accelerating jet of a gaseous fluid against successive increments of the at least one flow in the conveyor. Such nozzle can be provided with at least one substantially slit-shaped fluid discharging orifice, and the orifice can extend at least substantially transversely of at least a portion of the elongated path. The at least one speed changing means can further comprise an arcuate surface which bounds a portion of the elongated path between the at least one nozzle and the at least one outlet of the conveyor; the at least one nozzle can be provided with an orifice which is arranged to discharge into the elongated path at least one jet of a suitable gaseous fluid along an arcuate path which merges gradually into the elongated path. At least one of the just discussed paths can have an arcuate shape, at least at the location or locus of merger of the second path into the elongated path.
The speed changing means of the improved apparatus can have a plurality of discrete speed changing devices at least one of which preferably includes at least one nozzle which is arranged to direct at least one particle accelerating jet of a gaseous fluid against successive increments of the at least one flow of particulate material in the conveyor.
The conveyor can be assembled of two or more neighbouring conveyor sections, and the at least one speed changing means can include a gas discharging nozzle having an orifice which is defined by two neighbouring sections of such conveyor.
The improved apparatus can further comprise means for controlling or regulating the operation of the conveyor and/or of the compacting unit. Such regulating or control means can comprise at least one sensor which is set up to monitor the thickness of the at least one flow of particulate material in the elongated path and/or the density of the at least one flow in the elongated path and/or the pressure of air in a chamber which is adjacent the elongated path in the region of the at least one outlet of the conveyor.
Another feature of our invention resides in the provision of a method of making at least one flow of particles of fibrous material, for example, randomly intermixed and/or interlaced tobacco shreds and fragments of tobacco ribs. The improved method comprises a first step of advancing a stream of particles from a first path into an inlet of an elongated second path having at least one outlet which is remote from the inlet. This first step includes compacting successive increments of the stream at the inlet of the second path with attendant interlacing and/or intermixing of at least some particles in successive increments of the thus obtained at least one flow, and the method further comprises the step of accelerating successive increments of the at least one flow in the second path to thus at least substantially singularize and/or otherwise loosen the particles not later than at the at least one outlet.
The accelerating step can include directing at least one jet of air or another suitable gaseous fluid against successive increments of the at least one flow in the second path.
The advancing step can further include moving the stream at a first speed, and the compacting step can include reducing the speed of successive increments of the stream from the first speed to a second speed; this compacting step can include directing at least one second jet of a gaseous fluid against successive increments of the at least one flow in the second path. The speed reducing step can include reducing the speed to approximatey a fifth or even a tenth or even less in comparison to a maximum speed of the stream of particles before the step of accelerating successive increments of the at least one flow in the second path to thus at least substantially singularize and/or otherwise loosen the particles.
The accelerating step can be carried out in a predetermined portion of the second path, and the method can further comprise the step of densifying the at least one flow between the inlet and the predetermined portion of the second path.
The compacting step can include imparting to successive increments of the at least one flow a density which is at least substantially uniform as considered transversely of the second path.
The accelerating step can include propelling the particles along the second path at least substantially in a direction toward the at least one outlet of the second path.
The method can further comprise the step of regulating the speed of the at least one flow in the second path and/or the speed of the at least one jet. This regulating step can include establishing a pressure differential between longitudinally spaced apart sections of the elongated second path.
The accelerating step can further include causing successive increments of the at least one flow to advance along a guide surface which bounds at least a portion of the second path, and establishing a flow of gaseous fluid between the guide surface and the at least one flow in the second path, which is nearby the guide surface.
The stream can constitute a sifted mass of tobacco particles. The wording sifted mass also means winnowed mass with respect to this invention.
The improved method can further comprise the step of discharging successive increments of the at least one flow from the at least one outlet of the second path into a rod forming station of a cigarette rod making machine or another tobacco rod making machine. Under such circumstances, the advancing and accelerating steps can be carried out in a distributor or hopper of the tobacco rod making machine. Such method can further comprise the step of withdrawing some (surplus) gaseous fluid by suction from the second path upstream of the at least one outlet. The advancing step can include advancing tobacco particles and/or other particles into a second path which has a plurality of outlets, one for each of a plurality of discrete flows of particulate material in the conveyor which defines the second path or paths. The tobacco rod making machine can be arranged to convert the discrete flows of tobacco particles into two discrete tobacco rods. Under such circumstances, the advancing step can include establishing two discrete second paths each of which extends from the inlet to a different outlet.
The improved method can further comprise the step of subdividing the stream in the at least one second path into a plurality of flows subsequent to the accelerating step.
The novel features which are considered as characteristic of the invention are set forth in particular in the appended claims. The improved apparatus itself, however, both as to its construction and the modes of assembling, installing and operating the same, together with numerous additional important and advantageous features and attributes thereof, will be best understood upon perusal of the following detailed description of certain presently preferred specific embodiments with reference to the accompanying drawings.